Telephone-exchange system.



H. P. 'CLAUSEN.

TELEPHONE EXCHANGESY'STEM.

APPLICATION FILED'MAR.15.1915- Patented 001;. 3,1916.

I 0:233 .QU aulo R lnvenlor fiC/ausen W/fnesses UNITED STATES PATENT OFFICE;

HENRY P. CLAUSEN, OF MOUNT VERNON, NEW YORK, ASSIGNOR, BY MESNE ASSIGN- MENTS, TO WESTERN ELECTRIC COMPANY, INCORPORATED, A CORPORATION OF NEW YORK.

TELEPHONE-EXCHANGE si's'rEM.

Application filed March 15, 1915. Serial No. 14,364.

To all whom it may concern:

Be it known that I, HENRY I. CLAUSEN. a citizen of the United States, residing at Mount Vernon, in the county of \Vestchester and State of New York, have invented certain new anduseful Improvements in Telephone-llxchange Systems, of which the following is a full, clear, concise, and exact description.

This invention relates to telephone exchange systems, and more particularly to such systems of the central energy type, the object of this invention being to provide improved signaling means for such systems.

Inaccordance with one feature of this invention, means are provided at the central oiiice whereby, after an operator has answered a call and the calling end of a link circuit has been connected to a called line, the calling subscriber may, by restoring the receiver to the switchhook and subsequently removing the receiver therefrom, cause the operation of recall signaling means at the central office, notifying the operator that the calling subscriber desires a different connection.

In accordance with another feature of this invention, means are provided at the central oflice whereby, after the operator has connected the calling line with a called line by means of a link circuit, and should the operator be talking with another calling subscriber or be absent from the position of the switchboard, the calling subscriber may,

by restoring the receiver to the switchhook, cause the disconnection of the link circuit from the called subscribers line.

This invention, which is an improvement upon the system disclosed in my application Serial No. 2553, filed January 16, 1915, is illustrated in the accompanying drawing in which all apparatus is shown in its normal and unactuated condition.

There is shown in the drawing a telephone exchange system containing one embodiment of this invention and comprising the usual subscribers stations, A and B, and a cord circuit C located at a central office for interconnecting the subscribers stations. It is believed that this invention will be fully understood from a description of the operation of the system shown in the drawing, and it will be so described.

Assuming that the operator is at a posi-v tion of the switchboard in which cord circuit C is located, plug connected to the leads from an operators telephone set will be inserted in jack 6, thereby opening contact 7 Supposing subscriber A wishes to converse with subscriber B, A removes the rece ver from the switchhook, thereby completlng a circuit from battery 8 through one winding of line relay 9, contact 10 of cutoff relay 11, line wires 12 and 13, contact 14 of cutoff relay 11 and the other winding of line relay 9 to battery 8. Current in this path actuates line relay 9, completing a circuit from line signal 15. The operator observing the line signal 15 inserts the answering plug into the jack indi cated by the signal 1:"), and thereby completes a circuit from battery 20, through contact 21 of relay 22, supervisory signal 23, resistance 24, sleeve contacts of the answering plug and jack,'and the winding of cutoff relay 11 to ground. Current in this path actuates the cutoff relay 11 which severs the circuit of the line relay 9, efl'acing the line signal 15. T he insertion of the answering plug also completes a circuit from battery 25 through -one winding of the relay 26, ring stand 27 ring contacts of the answering plug and jack, line wires 12- and 13, tip contacts of the jack and answering plug, t1p strand 28, through the other winding of relay 2G to battery 25.

Current in this path actuates the relay 26,

opening contact 29 thereof, which removes the short circuit from resistance 24, thereby preventing the operation of the supervisory signal 23. The actuation of relay 26 also closes contact 30, completing a circuit from battery 25, through contact 30 of relay 26, contact 31, of relay winding of relay 33, sleeve contacts of the answering plug and jack, and the winding of cutoff relay 11 to ground. Current in this path actuates relay 33, connecting the operators telephone set across the tip and ring strands 34 and 35 of the cord circuit. The actuation of relay 33 also opens contact 36 and closes contact 37. The operator now asks the desired number of the calling subscriber. Finding the desired number to be that of subscriber B, the operator touches the tip of the calling plug to the sleeve of the jack corresponding to Bs line to determine the idle or busy condition thereof.

Patented Oct. 3, 1916.

If the line tests idle, the calling plug is inserted into the jack, completing a circuit from battery 50, through the winding of relay 32,,contact 51 of relay 52, sleeve contacts of the calling plug and jack, and

winding of cutoff relay 53 to ground. Current in this path actuates the cutoff relay 53, cutting line relay, 54 from line wires 55 and 56, and actuates relay 32 which opens contact 31, thereby releasing relay 33 and disconnecting the operators telephone set 39 from the cord circuit, and closes contacts 57 and 58. The insertion of the calling plug also completes a circuit from battery 65 through contact 66 of relay 67, supervisory signal 68, contact 51 of relay 52, sleeve contacts of the calling plug and jack, and winding of the cutoff relay 53 to ground, operating supervisory signal 68.

To signal subscriber B the operator now depresses a button of locking ringing key 69 to which is connected a source of ringing current of the frequency to .which ringer 70 at station. B is tuned, and in so doing closes a non-locking way-down contact 71, completing a circuit from battery 25, through contact 30 of relay 26, contact 57 of relay 32, winding of relay 72 and con-v tact 71 to ground. Current in this path actuates relay 72, completing a locking circuit therefor through contact 73 thereof and contact 74 of marginal relay 75 to ground, opening contacts 76 and 77, and closing contacts 78 and 79. The opening of contacts 76 and '77 opens the tip and ring strands 34 and 35 of the cord circuit, and the closure of contacts 78 and 79 connects ringing current to one side of the line and ground to the other side. The path for ringing current may be traced from ringing key 69, through winding of marginal relay 75, contact 79 of relay 72, contact 80 of relay 52, ring contacts of the calling plug and jack, line wire 56, ringer 70, condenser 81, line wire tip contacts of the jack and calling plug, contact 83 of relay 52 and contact 78 to ground- Relay ,75 is marginal and will not operate when in series with the ringer and the condenser 71, but

will operate when the ringer and condenser are shunted by a path of low resistance.

The called subscriber, upon removing his receiver from the switchhook, closes a path of low resistance for the ringing current, thereby permitting a greater flow of current through relay 75, which is thereupon actuated, opening'the locking circuit of relay 72 at contact 74. Relay 72 thereupon releases, removing ringing current from the line and closing the tip and ring strands 34 and 35 of the cord circuit, thereby completing the talking circuit. The release of relay 72 completes a circuit from battery 86 through one winding of relay 67 to ring strand 35, contact 77 of relay 7 2, contact of relay 52, ring conductors of the calling 'return to normal.

plug and jack,- line wires 56 and 55, tip contacts of the jack and calling plug, contact of relay 52, contact 76 of relay 72, tip strand 34 and the other winding of relay 67 to battery 86. Current in this path actuates relay 67 which opens contact 66, removing the short circuit from about resistance 87, thereby effacing supervisory signal 68.- Upon finishing the conversation, subscribers A and B restore their respective receivers to the switchhooks, whereupon relays 26 and 67 release, permitting supervisory signals 23 and 68 to operate to furnish disconnect signals. If the operator is not busy, the answering and calling plugs are removed from the jacks and all apparatus Suppose, however, that as is frequently the case during busy periods, the operator does not immediately take down the connection, and suppose further that subscriber A desires to immediately make another call. He removes his receiver from the switchhook, thereby causing supervisory signal 23 to intermittently flash, signifying to the operator that subscriber 90 A desires another connection. The manner in which supervisory signal 23 is caused to flash intermittently will now be described. \Vhen As receiver was restored to the switch hook upon the completion of the conversation, a circuit was completed from battery 90, through winding of relay 91, contact 36 of relay 33, contact 29 of relay 26, sleeve contacts of the answering plug and jack, and winding and cutoff relay 11 to ground. Current in this path actuates relay 91 which opens contact 92 and closes contacts 93 and 94. It is to be noted that the circuit of relay 91 will not be completed unless the calling plug is inserted into the jack of the called line. The removal of the receiver from the switchhook by subscriber A to make a recall (another call) causes relay 26 to be actuated over the circuit hereinbefore traced. The actuation of relay 26 opens contacts 29 and closes contact 95, completing a circuit from battery 96, through the winding of relay 22, contact 95 of relay 26, contact 94 of relay 91, sleeve contacts of the answering plug and jack, and the winding of cutoff relay 11' to ground. Current in this path actuates relay 22 which opens contact 21 and closes contact 97. The closing of contact 97 completes a circuit from battery 98, through interrupter 99, contact 97 of relay 22, supervisory signal 23, contact 94 of relay 91, sleeve contacts of the answering plug and jack, and the winding of cutoff relay 11 to ground, causing supervisory signal 23 to flash intermittently to furnish a recall signal.

The operator observing that supervisory signal 23 is flashing and that supervisory signal 68 is glowing steadily, removes the which in releasing causes relay 22 to re lease. Relay 22 in releasing removes the interrupter 99 from the circuit including the supervisory signal 23. The operators telephone set being connected to the line, theoperator now communicates with subscriber A andcoinpletes the desired connection in the manner already explained. Instead of removing the calling plug, the operator may simply operate keyllO, completing a circuit from battery 111 through the winding of relay 33. which operates and connects the operators telephone set across the line.

It is to be understood that there are other cord circuits exactly like cord circuit C at the central office and that subscribers lines other than those of A and B terminate at the central ofiice, but for the sake of simplicity and convenience only two subscribers lines and one cord circuit are shown. Relay 100 is common to all the cord circuits in one position. The various leads 101 from this relay terminate in normally open contacts 7 (open when plug 5 is inserted in jack 6) and 37 of the various cord circuits. Likewise, normally open contact 102 of relay 100 is common to all of the cord circuits in one position of the switchboard and lead 103 connects the armature of the relay 100 with one winding of relay 52 in each of the cord circuits. Now, if subscriber A, after the calling plug of the cord circuit has been connected with the jack of HS line, desires to call another line instead of Bs line, it will frequently happen that subscriber B removes his receiver from the switchhook in response to the signal from ringer 70, and if the recall signal has been given by subscriber A, considerable confusion exists due to the fact that A and B are connected. Consequently it is desirable that should the operator be busy when subscriber A makes a recall, the cord circuit will be disconnected from Bs line in such a manner that when B responds, the line signal associated with this line will be operated and an operator may go in on the line and make the necessary explanation to subscriber B. In accordance with this in vention, if the operator is busy when subscriber A makes a recall, the cord circuit is automatically disconnected from Bs line; The manner in which this is accomplished will now be explained. Assuming that the operator at this position has inserted the answering plug of a second cord circuit into to ground.

relay 100 which closes its contact 102. Now

the jack of another calling line, relay 33 of the second cord circuit will be operated in a manner similar to that hereinbefore explained for relay 33 of the cord circuit C. The operation of relay 33 in this second cord circuit closes its contact 37, whereupon a circuit is completed from battery 105 through the winding of relay 100, lead 1'01 and contact 37 of the second cord circuit Current in this path actuates;

suppose that subscriber A has restored the receiver to the switchhook and that the circuit of relay 91 has been completed in the manner hereinbefore described, a circuit will be completed as follows: from battery 90 through contact 93 of relay 91, contact 58 of relay 32, winding 106 of relay 52, and contact 102 of relay 100 to-ground. Current in this path actuates relay 52 which opens its contacts 51, 80 and 83 and closes contact 107, thereby completing a locking circuit for relay 52 from battery 50, through the winding of relay 32, contact 107 and winding 108 of relay 52, sleeve contacts of the answering plug and jack and the winding of cutoff relay 11 to ground. It will be seen therefore that the operation of relay 52 opens the tip and ring strands of the cord circuit C at contacts 80 and 83 and also opens the sleeve strand of the cord circuit at contact 51, thereby permitting cutoff relay 53 to release, connecting line relay 54 to the line wires 55 and 56 of substation B. It will be observed that supervisory signal (38 will remain energized after relay 52 operates. In order to cause relay 52 to release, the answering plug of the cord circuit 0 must be removed from the jack of As line. Since contacts 7 and 37 of each cord circuit are in multiple, the cord circuit C may be disconnected from Bs line by the operator removing plug 5 from jack 0 when leaving the position.

\Vhile in this description many batteries have been referred to, it is to be understood that a common battery may be substituted therefor and such is the usual practice.

What is claimed is:

1. In a telephone exchange system, calling and called subscribers lines, a link cir-- cuit, switching means connecting said link circuit with said lines, recall signaling means permanently associated with one end of said link-circuit and forming a part thereof, means associated with the opposite end of said link circuit for disconnecting said link circuit from the line without disturbing the switching means, and means under the joint control of one of the connected subscribers and the operator for controlling the operation of said recall signaling means and said disconnecting means.

- 2. In a telephone exchange system, calling and called subscribers lines, link circuits, switching means for connecting said connection of link circuit-with a calling line,

means jointly controlled by the restoration to the switchhook of the calling subscribers receiver and by the operation of said operators telephone set connecting means of a second link circuit for operating said disconnecting means, and means jointly controlled by the restoration to the switchhook of the calling subscribers receiver and a subsequent removal thereof and the connection of the switching means with a called line for operating said flashing recall signaling means.

3.. In a telephone exchange system, calling and called subscribers lines, a link circuit, switching means for connecting said link circuit with said lines, a disconnect relay associated with one end of said link circuit for disconnecting said link circuit from the line connected with that end without disconnection of the switching means, a circuit for said disconnect relay open at two points, -a second link circuit, switching means associated with said second link circuit operating automatically when said second link circuit is connected with a line to cause the closure at one point of said disconnect relay circuit, the restoration to the switchhook of the receiver of one of the subscribers connected with said first link circuit, and a subsequent removal thereof causing the final closure of said disconnect relay circuit.

4. In a telephone exchange system, calling and called subscribers lines, a link circuit, switching means for connecting the link circuit with said lines, a disconnect relay associated with one end of the link circuit for disconnecting the link circuit from the line connected therewith without disconnection of theswitching means, a second link circuit and apparatus associated therewith, and an energizing circuit for the disconnect relay jointly controlled from a subscribers station connected with the first link circuit and by the apparatus associated with the second link circuit.

In a telephone exchange system, calling and called subscribers line, a link circuit, switching means for connecting the link circuit with said lines, a disconnect relay associated with one end of the link circuit for disconnecting the link circuit from the line connected therewith without disconnection of the switching means, an operators plug and jack, a second link circuit, apparatus associated therewith and operated when the second link circuit is connected With a line, and an energizing circuit for the disconnect relay jointly controlled from a subscribers station connected with the first link circuit and by the apparatus of the second link circuit when operated or the disengagement of the operators plug and 'ack. J In witness whereof, I hereunto subscribe my name this 13th day of March A. I)., 1915.

HENRY P. CLAUSEN.

Witnesses:

E. EDLEIL, K. L. STAHL. 

